Aqueous emulsion of unvulcanized rubber and sulphur



Patented June 15, 1926.

UNITED STATES PATENT OFFICE.

SAMUEL E. snErrARn AND LEoN W. EBERLIN, or RocnEs'rER, NEW YORK, As- SIGNORS 'ro EASTMAN xonnx COMPANY, or ROCHESTER, NEW YORK, A can- PORATIQN OF NEW YORK.

AQUEOUS EMULSION OF, UNVULGANIZED- AND SULPHUR.

No Drawing.

This invention relates to aqueous emulsions of unvulcanized rubber and sulphur. One object of the invention is to provide an improved emulsion of thisvcharacter suitable for electrodeposition by the process disclosed in our U. S.' Patent No. 1,476,374, granted loid, preferably of a' gelatinous nature. We

shall now describe one specific embodiment of our invention by way of illustration, but it will be understood that our invention is not limited thereto nor to the details thereof, except as indicated in the appended claims.

To an aqueous rubber emulsion, such as one prepared in accordance with our above cited patent, or a natural one, such as rubber latex, preferably made stable 'by an alkaline agent, such as ammonia, we add an aqueous emulsion of sulphur containing the protective colloid. We may, for example, prepare an aqueous solution of gum arabic or gelatin or glue having a concentration of about- 5%. Into this we disperse the sulphur, say 20%. This dispersing may be accomplished by any of the means known in this art, such as by precipitation or agitation. One convenient way is to mix the sulphur into said solution in finely divided form, like flowers of sul-- phur, andthen pass the mixture through a high-speed colloid mill of any of the types now on the market.

The aqueous emulsion of sulphur and col loid is then thoroughly mixed with the aqueous emulsion of unvulcanized rubber. For example, wemay add 1000 cc. of the above described sulphur emulsion to 4000 cc.

of rubber latex, preferably one having about 30% concentration ofrubber. The latex may be sufficiently alkaline to prevent coagulation, orthe sulphur solution may be made Application filed- Apri1 7, 1925.. seria vo. "21,340.

slightly alkaline, say with ammonia before .it is stirred into the latex. Similar proportions and-expedients are employed when the sulphur-colloid emulsion is incorporated in the emulsion of unvulcanized rubber disclosed in our above cited patent.

The protective colloid may be worked into the rubber emulsion by addition of one or more pigments. Thus we may mix 4% carbon-black in an aqueous solution containing of a per cent of colloid such as glue, the mixture being .homogenized by intensive agitation, say in one of the known colloid mills. The emulsion thus produced is then mixed into a rubber emulsion, such as the latex above described and the combination homogenized in a suitable mill. We may employ, for example, .3000 parts by volume of the carbonblack-colloid emulsion to 4000 parts of the 30% rubber emulsion or latex. Where a white pigment is desired, we may mix 20% of zinc oxide in a solution of glue and homogenize to get a stable emulsion, which is then incorporated with the latex or emulsion of unvulcanized rubber in a way similar to that he-reinabove described.

Similarly, nigrosine can be emulsified with a colloid and added.

The method is also applicable to the incorporation of diphenyl guanidine, as an accelerator of vulcanization. Thus we prepare an 8% suspension of this substance in water and mix it with. the rubber emulsion or latex, in the proportion of 1000 parts by volume of the former to 4000 parts of the latex.

While We may add any of the above mentioned emulsions containing the colloid to the rubber emulsion and homogenize the mixture, with suitable low-speed mills, we may also simultaneously add any two or more of them. In fact, in the preferred form of our invention we add to the rubber emulsion or latex all of the ingredients hereinabove described in the proportions stated, thus obtaining an emulsion of unvulcanized rubber carrying sulphur, diphenyl guanidine, carbonblack, nigrosine and zinc oxide together with the gelatinous colloid.

The hereinabove'described emulsions may all be utilized in the process of electrodeposition described incur above cited patent. The conditions there given, namely,-the use of 110 volts and a current density of ,aresatisfactory.

1 Having thus'des'cribed our invention, what f; we claim as'newand desire'to secure by Letfters Patent is: j c 1. Ani' aqueous emulsion com rising in the =-'dispe rsey phase electrodeposita le unvulcanized 'rubber, vulcanizing material, and an organic'protective colloid, swellable inwater. 2.] An aqueous emulsion comprising in the isperse phase electrodepositable unvulcanized rubber,.sulphur, and an organic protec tive colloid,"swellable in Water.

3.- An aqueous emulsion comprising in the i'zed; rubber, '-Vulcanizing material, and a {gelatinous protective colloid. I v 4'. An'aqueous emulsion comprising in the disperse phaseelectrodepositable unvulcanzo lized rubber, sulphur, and glue. 1 '5. An aqueous emulsion comprising in the disperse phase electrodepositable 'unvulcanizied rubber,.- vulcanizing material, coloring ,matter,- and an organic protective colloid, 2'5 'swellable in Water. p r

6'. The process of preparing an aqueous emulsion containing in the disperse phase 7' i electrodepositable unvulcanized rubber, Vul-' canizing material, and a protective colloid, which comprises the steps of mixing an and subjecting the mixture to agitationiuntil perse phase electrodepositable unvulcan aqueous emulsion .of unvulcanized rubber with an aqueousfemulsion of vulcanizing material, 1n the presence of a protective colloid homogenized. 4 v

7 The'process of preparing an aqueous.

'en1ulsion -compr1sing in the disperse phase electrodepositable unvulcanized rubber, sul-' phur, and a protective colloid, Which comprises the steps of mixing an aqueous emulsion of rubber and an aqueous emulsion of sulphur in the presence of a protective cblloid, and then subjectingthe mixture to agitation until the emulsion is homogenized.

8 The process of preparing an aqueous emulsion Containing in the disperse phase electrodepositable rubber, and --a-. plurality of substances which cooperate Withthe rubber in an electrodeposited coating made from said emulsion, which comprises the steps of 60 preparing a plurality of separate aqueous emulsions of said unvulcanized rubber and said substances, mixing said aqueous emulsions together, and subjecting the mixture to agitation until a stable mixed emulsion is obtained. I Signed at Rochester New York this 2nd day of April, 1925.

i SAMUEL E. SHEPPARD.

LEON W. EBERLIN. 

